Note on Comparative Ranks: Rank structures and titles in the various armies of the Great War were not exactly equivalent. In the French Army there were only two permanent general officer ranks: General of Brigade and General of Division. A General of Army Corps or a General of Army was actually a General of Division appointed to that higher command; he wore the insignia and used the title of his appointment during his tenure in command only. (The title of Marshal of France was not a rank but an honorific, conferred for distinguished service.)
In the German Army general officer ranks were permanent. These were Colonel-General (Generaloberst) General of Arm or Branch (General der Waffengattung), Lieutenant-General (Generalleutnant) and Major-General (Generalmajor). A General of Arm or Branch used the name of his parent branch of service, e.g. General of Infantry (General der Infanterie). The highest Army rank was Field Marshal (Generalfeldmarschall); in 1914 no general officer on the active list held this rank, which by custom was only conferred for distinguished service in wartime. Kaiser Wilhelm II held it ex officio as monarch and “Supreme Warlord.”
In the British Army also general officer ranks were permanent. These were Field Marshal, General, Lieutenant-General, Major-General and Brigadier-General.
For clarity, German formations are rendered in italics.
The first campaign of the Great War in the west was dominated by two factors: Germany’s amended Schlieffen Plan (already described) and France’s Plan XVII. The latter was a straightforward proposition: a mobilization and deployment scheme anticipating an all-out offensive, the objective of which was to clear German forces from Alsace and Lorraine and carry the French armies to the Rhine River. For this purpose France’s five field armies were to be concentrated between the Belgian and Swiss borders. On the left, Fifth Army was to act as a flank guard in case the Germans attempted an attack through Luxembourg and southern Belgium. The remaining armies — from left to right the Fourth, Third, Second and First — were to drive into Lorraine and northern Alsace. To the south of this main effort, a detached corps would advance into Alsace toward the city of Mulhouse. Map 1 shows the deployment areas of the French and German armies on 2 August. Note how the concentration on the German right flank overlaps the French left.
Though the French commander-in-chief, General Joseph Joffre, recognized the possibility of a German flank attack through southern Belgium he never seriously considered the idea of a large-scale German maneuver on the pattern of the Schlieffen Plan. Joffre reasoned that the Germans possessed insufficient first-line divisions for such an audacious operation. Discounting the value of his own reserve divisions, he failed to foresee that the Germans would use theirs in an offensive role. Thus the Fifth Army, supplemented by the British Expeditionary Force (Field Marshal Sir John French), seemed to him adequate to secure the French left flank. He paid no attention to the warnings of Fifth Army’s commander, General Charles Lanrezac, that the Germans were deploying in great strength along their border with Belgium. Lanrezac was uncomfortably aware that between his left flank and the Channel coast there was nothing more than a thin screen of second-line Territorial troops along the Franco-Belgian border. As for the BEF, it had arrived in France by mid-August but had not yet taken up its post to the left of Fifth Army.
Joffre’s strategic misjudgments were compounded by serious tactical deficiencies. In the years prior to the war the French Army had fallen under the sway of a faction that preached the doctrine of the offensive in its most extreme form. All professional soldiers in Europe felt similarly, of course, but in France the offensive was embraced with almost religious fervor. Relying on an aggressive spirit supposedly native to the French soldier, the armies would plunge ahead in dense formations, supported by the rapid fire of the excellent French 75mm field gun, overrunning the enemy in one audacious rush.
There were, indeed, doubters and critics. Some argued that insufficient attention had been paid to infantry tactics or to the problems of coordination between infantry and artillery. Others noted that in the face of modern firepower, attacks relying on mass and shock were unlikely to succeed. Still others pointed to the French Army’s material deficiencies, especially in medium and heavy field artillery. These criticisms the prophets of the offensive waved away with assurances that French cran — guts — would compensate for any such shortcomings. To suggestions that the traditional infantry uniform — dark blue coat, madder red trousers — should be replaced by something less conspicuous, they replied scornfully: Les pantalons rouges, ils sont la France!
Given this background, what happened when Joffre launched his offensive may readily be inferred. Between 14 and 23 August the French First Army (General Augustin Dubail) and Second Army (General Édouard de Castelnau) were bloodily repulsed at all points in Lorraine. Attacking in close-packed formations, bayonets fixed, regimental colors and saber-waving officers in front — sometimes even with bands playing — the French infantry were mowed down in droves by rifle, machinegun and artillery fire. Against German troops in well-sited defensive positions the 75mm field gun proved ineffective, and in their gaudy uniforms the French troops made perfect targets. Only in southern Alsace, where the defending Germans were weakest, did the French enjoy some measure of success — but the ground gained there was mostly yielded back after the disaster farther north.
Preoccupied with the fortunes of his attacking armies Joffre was slow to recognize the danger looming on his left flank. The information that did come to hand convinced him that the Germans were attempting no more than the anticipated flank attack through southern Belgium. He therefore ordered Fifth Army to sidestep to its left, establishing touch with the BEF, now in the field with four infantry divisions, a cavalry division and an independent cavalry brigade. (The BEF was supposed to have been six infantry divisions strong but an invasion scare led the British government to hold two divisions back.) The Third Army (General Pierre Ruffey) and Fourth Army (General Fernand de Langle de Cary) were ordered to advance into the Ardennes, there to blunt the German advance. The French attack in this sector began on 21 August but as in Alsace-Lorraine broke down amid heavy casualties. Map 2 shows the French offensives in Alsace-Lorraine and the Ardennes, and the subsequent German counteroffensive.
Meanwhile the German right wing, consisting of First, Second and Third Armies, was advancing through Belgium. First Army (Colonel-General Alexander von Kluck) initially moved northwest, engaging the Belgian Army (six infantry divisions and a cavalry division) on 17 August. After a hard-fought action, the Belgian commander, King Albert, ordered his army to withdraw into the fortified position around Antwerp. Thereupon First Army turned left toward Brussels; the Belgian capital fell on 20 August. Meanwhile, Second Army (Colonel-General Karl von Bülow) and Third Army (Colonel-General Max von Hausen) advanced into the gap between the Belgians and the French Fifth Army. Fifth Army, stretching its left flank northward, found itself badly outnumbered and was driven back by Second and Third Armies. This heavy pressure on the French left also forced the Fourth Army to give ground. Meanwhile the advance of First Army had brought it into contact with the BEF, deployed in defensive positions around the town of Mons. After a hard-fought battle there on 23 August in which the Germans suffered heavily from the rapid, well-directed rifle fire of the British infantry, the BEF was compelled to fall back.
The Battle of the Frontiers was over, a grievous and costly French defeat, and the Great Retreat was underway. Map 3 shows the advance of the German right wing up to 26 August. Note how First Army’s line of advance from Brussels has diverged from that laid down in Schlieffen’s original plan: a change of direction that was to have fateful consequences.
But not all was well on the German side. At the headquarters of OHL (Oberste Heeresleitung or Army High Command) in Trier, General von Moltke fretted. His armies had done well thus far but where were the spoils of decisive victory: prisoners, captured guns and impedimenta? What was happening at the front? As the field armies advanced, communications between them and OHL became fitful and uncertain. And from the east, where a mere fraction of the German Army stood in defense of East Prussia, there came grim tidings of a massive Russian offensive. As the terrible uncertainties accumulated, the nerves of the Chief of the Great General Staff began to fray.